Dissolution of metals utilizing a H2 O2 -H2 SO4 solution catalyzed with hydroxy substituted cycloparaffins

Abstract

Improved metal dissolution rates are obtained when using a solution containing sulfuric acid, hydrogen peroxide and an effective amount of a mono- or dihydroxy-substituted cycloparaffin.

What is claimed is: 
     
       1. In a process for the dissolution of metal in which a metal is contacted with an aqueous solution containing from about 0.2 to about 4.5 gram moles per liter of sulfuric acid, from about 0.25 to about 8 gram moles per liter of hydrogen peroxide, the method of increasing the metal dissolution rate of the solution to a value higher than that obtained by such a solution free of any chloride and bromide ions, which method comprises adding at least about 0.085 and up to 0.5 gram moles per liter of the solution of a promoter selected from: (a) monohydroxy or dihydroxy-substituted cycloparaffins containing from 5 to 7 carbon atoms in the ring structure, or   (b) monohydroxy or dihydroxy-substituted alkylcycloparaffins containing from 5 to 7 carbon atoms in the ring structure, where each of the alkyl groups contains from 1 to 4 carbon atoms and is attached to an unsubstituted carbon atom in the ring structure.   
     
     
       2. The method of claim 1, wherein the aqueous solution contains sodium phenolsulfonate as a stabilizer to reduce the degrading effect of heavy metal ions on hydrogen peroxide. 
     
     
       3. The method of claim 1, wherein the hydrogen peroxide concentration is maintained between about 1 and about 4 gram moles per liter. 
     
     
       4. The method of claim 1, wherein the sulfuric acid concentration is maintained between about 0.3 and about 4 gram moles per liter. 
     
     
       5. The method of claim 1, wherein the promoter is cyclopentanol. 
     
     
       6. The method of claim 1, wherein the promoter is cyclohexanol. 
     
     
       7. The method of claim 1, wherein the promoter is cycloheptanol. 
     
     
       8. The method of claim 1, wherein the promoter is 1,2-cyclohexanediol. 
     
     
       9. The method of claim 1, wherein the promoter is 1,3-cyclohexanediol. 
     
     
       10. The method of claim 1, wherein the promoter is 1,4-cyclohexanediol. 
     
     
       11. The method of claim 1, wherein the metal is copper or an alloy of copper. 
     
     
       12. The method of claim 1 carried out in the presence of chloride or bromide ions in excess of 2 ppm and up to 50 ppm. 
     
     
       13. In a composition for metal dissolution comprising an aqueous solution of from about 0.2 to about 4.5 gram moles per liter of sulfuric acid and from about 0.25 to about 8 gram moles per liter of hydrogen peroxide, the addition of at least about 0.085 and up to 0.5 gram moles per liter of a promoter for increasing metal dissolution rate of the solution to a value higher than that obtained by such a solution free of any chloride or bromide ions, which promoter is selected from: (a) monohydroxy or dihydroxy-substituted cycloparaffins containing from 5 to 7 carbon atoms in the ring structure, or   (b) monohydroxy or dihydroxy-substituted alkylcycloparaffins containing from 5 to 7 carbon atoms in the ring structure, where each of the alkyl groups contains from 1 to 4 carbon atoms and is attached to an unsubstituted carbon atom in the ring structure.   
     
     
       14. The composition of claim 13, additionally containing sodium phenosulfonate as a stabilizer for reducing the degrading effect of heavy metal ions on hydrogen peroxide. 
     
     
       15. The composition of claim 13, wherein the hydrogen peroxide concentration is maintained between about 1 and about 4 gram moles per liter. 
     
     
       16. The composition of claim 13, wherein the sulfuric acid concentration is maintained about 0.3 and about 4 gram moles per liter. 
     
     
       17. The composition of claim 13, wherein the promoter is cyclopentanol. 
     
     
       18. The composition of claim 13, wherein the promoter is cyclohexanol. 
     
     
       19. The composition of claim 13, wherein the promoter is cycloheptanol. 
     
     
       20. The composition of claim 13, wherein the promoter is 1,2-cyclohexanediol. 
     
     
       21. The composition of claim 13, wherein the promoter is 1,3-cyclohexanediol. 
     
     
       22. The composition of claim 13, wherein the promoter is 1,4-cyclohexanediol. 
     
     
       23. The composition of claim 13 containing free chloride or bromide ions in excess of 2 ppm and up to about 50 ppm.